Removable adjusting attachment for drawing compasses and the like



Aug. 10, 1943. H. FRIEDMANN REMOVABLE ADJUSTING ATTACHMENT FOR DRAWING COMPASSES AND THE LIKE Filed June 17 1942 INi ENTOR.

BY: 6/: o/fiorn e3].

N N A m M H W M Patented Aug. 10, 1943 UNITED: STA -Es PATENT OFFICE QREM-OVABIYQE 'AJZJJUSTING ATTACHMENT FOR DRAWING COMPASSES AND THE LIKE Hugo Friedmann, Astoria, N. Y '7 Application June 17, 1942, Serial No. {147,354 6 Claims (01. 33-154) This invention relates to measuring and drawing instruments particularly to "those having two jointed legs, like compasses and dividers, and has for its main object to provide an attachment for such instruments whereby theymaybe' adjusted to a desired opening in a more'efficientand'precise manner than has'been done heretofore. -.Another object of my invention is to provide an attachment of the mentioned character whereby such instruments may beemploy'ed and used by one hand of the operator in the usual manner and with the same one hand they may also be r adjusted and set to a'desired openin'g'instea'd of using both hands as it is now necessary for such adjusting of these instruments.

' Still a further object of my invention is to provide an attachment as characterized hereinbefore which not only may be set very precisely and exactly to a desired opening withone hand and with great facility, but wherein such; adjusting and setting will be done in a mechanical way by a screw and wherein the instrument may be exactly fixed in the position into which it was adjusted and will not and can not change its adjusting and setting during any subsequent operations and uses as long as its adjusting and setting is not changed by the operator. l

Still another object of myinvention is to provide a device of this 'type'which maybe easily attached to such'instrurnents of practically any usual type particularly compasses, and as easily removed therefrom. V

Other-objects of I this invention willvbe apparent as a specification of the same'proceeds and, among others, I may mention: to provide a device of the'character indicated which will be simple in construction, inexpensive to manufacture, easy and reliable to apply and to operate, adapted to practically any instrument of the type mentioned, and which will permit wide limits in adjusting the same.

In the drawing formingfa partof this speck fication and accompanying the same:

Fig. 1 is a front elevational view of a pair of compasses with my attachment applied thereon;

, by characters of reference, the numeral I indicates my novel removable precision adjusting and setting device, as applied on a pair of drawing compasses, as an'example only, generally indicated by the numeral II. 1 I

My device discloses two clamping'members I2 andvI3, to be applied on the respective legs M l and I 5 of the compasses H through the screws l5 and IT, as will be more fully explained hereinafter. 1

Referring. to the clamping member I2; it is composed of a main body or-stein I8, generallyof rectangular cross section, which is terminated in upper and lower flanges IEI and '29,,turned inwardly, that is, toward the legof the compasses when the device is secured on such an instrument.

Leg M of the compasses will be set into the opening 2 I of the channel shaped clamping members I2, and will be secured therein by the screw I5, passing through a threaded hole 22 in the flange 29 and pressing againstleg I4 preferable by a plate or washer 23. Screw lfimay be operated'by'the headldisk'zd, and when driven inwardly it will press the leg I 4 againstthe opposite flange I9, and, vice versa, when moved outwardly, it will release the leg M. I V

A partly screw threaded hole 25 is provided through the upper flange I9 and a pin 28 is rotat-j ably arranged therein, its screw threaded inner 7 end 2'! being in engagement with the screw threaded inner portion of the hole 25. g

A ring 28 is secured. on the outer end of the pin 26, or these two parts may be made integral, in one piece, the hole 29 in the ring 28 beingscrew threaded in a certain direction, let' us say, as for a right handed screw.

The other channel form clamping member I3 is identical with member I2, just described, with the exception that its securing screw I! may be made considerably shorter than the screw I6 so that its head disk 2441 may be easily operated without at its center, the screw threads on its left hand portion 32 obviously being the same as those in the ring 28 and cooperating therewith, while the screw threads on its right hand portion 33 being oppositely directed and cooperating with the threads in ring 28a. V

The use and operation of my device will be understood from the description thereof by those versed in this art, but I may offer the following further explanation relating thereto:

As has been mentioned, my attachment may be a separate unit, applied to, or removed from,

' any suitable instrument, as desired, but it also moving the instrument from the job, only slightly lifting one leg, and keeping the other at the desired spot, while, of course, the whole instrument may be lifted off the job, somewhat, and the disk 3| turned in such a position if that is desired.

The setting is extremely fine and gradual so that no repeated trials are needed, the instrument is moved unhesitatingly to the right position in one continuous movement and; the setting may at once be made'just the rightone to the finest degree, as will be obvious. Indeed, I may call itamicrometer setting, right in a drawing or measuring instrument, if the screw threads shaped clamping members 12 and 13 are of such 7 a shape and size that they conveniently receive the legs of any usual drawing compasses, dividers, or'ot'her similar instruments.

In the instant case, clampingmember 'l2'will be placed on or, over a selected portion of leg 14 and secured thereon by the suitable turning and inward moving of the screw 11$.

Similarly, clamping memberifi will be placed on leg 15 and secured thereon by the screw IE, care being taken to place the two clamping memherein the right position on the respective legs, viz. at'the same distance from the pivot or joint 34 ofthe legs. v

Now 'up'on turning screw 3% one or in the other direction, by the manipulating knurled disk 31, theoppoSite screw threads 32 and 33'will in one case cause the rings 2-8 and 23a to move inwardly, toward one another, or, in the other case, outwardly, away from one another. The movement of the r-ings 2'8 and'28a willcarry the re- 1 spec'tive legs M and -l5 in a similar manner so that the opening of the pair of compasses l I will be reduced or increased.

It will be obvious that the -dev-ice isdimensioned in'such amanner that the compasses may bemoved to the smallest limit, that :isto zero distance, the two legs touching each other, or in the opposite direction, the rings 23 and 28a may be moved to the terminations 35 and 36 -of the screw 30 thereby setting the legs i l and IE to the greatest opening, which may be as large as may at any time be needed in ,theusual application of the instrument. The range of the ;opening will depend on the length'of the screw 36;

- 'Ipreferably leave a small spaceilitbbetween the" tops of the clamp members lz-an-d l3 and the rings '28 and 28a to permit an easier adjusting of therings to the angles of the legs l3 and f5 as they are-closingor opening.

I It also will be obvious that the hand operating tachrnent, the adjusting of the instrument to anydesired dista'nce will be'easy, convenient, automatic," mechanical, gradual, positive and precise,

, and thehand operating the instrument will be ableto do the adjustingtoo.

The adjusting, therefore, not only will be more handy and procise but it will also leave the other hand 'free.

The adjustment also maybe made without re- 32 and 33 aremade fine enough.

, Oncethe instrument is set by my attachment, it will belocked in such a position, and it will be insured that its distance will not change as long as the operator does not change it by the use of the manipulating disk 3!, the present dangerof the instrument moving and changing. after an adjustment is, therefore, entirely eliminated when my attachmentjis used thereon. This is especially importantwhen it is desired to repeatedly mark the same distance.

It also will be obvious that my attachment may be used on other instruments than of the jointed leg type as long as they have two measuring or drawing elements which move toward or away from one another for setting. The manipulating disk 31 also may be arranged in other appropriate positions than in the middle? of the screw 30, like at anendthereof. 1

My invention maybe applied to practically any instrument of this typeas it will be easy to secure its two clampingmembers on the moving measuring or drawing elements and it may be used on drawing and shop'instruments, as an example, the use of the large'wooden compasses for drawing on a blackboard in school rooms will be greatly facilitated, for which purpose my attachment may be made of wood too, with steeper screw helices for quick adjusting.

Throughthe use of my attachment any pair of compasses may be made into a precision instrument, even the cheapest school sets, and a worn, faulty instrument, shaky and with plenty of lost movement, may be made firm and exact.

Compasseswith my attachment will be very useful when it is desired to draw several very close, hairline, circles from one center, which through it may be done without lifting-the pointed end of the instrument from said center. 7

It willbe seen that I have shown and described 5 an attachmentfordrawing and measuring instruments embodying the principles and attaining the mentioned objects of the present invention.

Since many matters of operation, interaction, combination, arrangement and structure may be variously modified without departing from the inventive principles herein, it is not intended to limit the invention to the details of thepresent embodiment, and 'I desire to reserve my rights to all changes and modifications as are within the spirit of this specification and within the scope of the claims hereunto appended.

What I claim as new and want to protect by apatent of the United States, is:

1. In an adjusting and setting attachment for drawingand measuring instruments, like compasses and dividers, having'two joined legs, and

a rod having opposite threads at its two sides from about itscenter, whereby to cause said legs to move closerto or 'further away from one another, a U shaped member embracing each leg, means to removably secure one of the flanges of the U in each member on the respective leg,

and oppositely screw threaded openings in said members for the respective threads of said rod.

2. In an attachment, as set forth in claim 1, a

rotatable pin projecting outwardly from the other flange of each member, aring at the free end of said rotatablepin, said screw threaded openings being in said rings.

3. In a device to set two movable elements means to removably secure one of the flanges of the U in each member on the respective element,

able pin projecting outwardly from each memher, a ring on the free end of each pin, said 0ppositely screw threaded openings being in said rings.

5. In a device, as set forth in claim 3, a rotatable pin projecting outwardly from each member, a ring on the free end of each pin, said oppositely screw threaded openings being in said rings, said removable securing means for the U said holes being arranged on said U shaped mem 20 bers.

shaped members on the respective elements being in the form ofa screw passing through one of the flanges of the U, and engaging the respective element, and said pins being arranged in the other flange of the U shaped members.

6. In a device, as set forth in claim 3, a rotatable pin projecting outwardly from each member, a ring on the free end of each pin, said oppositely screw threaded openings being in said rings,- said pins being inwardly or outwardly movable to adjust the distance of said rings from the'recess in said U. l

v l HUGOFRIEDMANN. 

